The armature winding of a 2-pole, 3-phase alternator for each phase is distributed in a number of slots per phase. The RMS value of the voltage per phase is less than the RMS value of the voltage per coil multiplied by the number of coils in series because the ________

A 3-phase, 4-pole alternator has 48 stator slots carrying a 3-phase distributed winding. Each coil of the winding is short chorded by one slot pitch. The winding factor is given by ______________

A

(cos7.5)/16

B

(cot7.5)/8

C

1/(8sin7.5)

D

(cot7.5)/16

A 6-pole alternator with 36 slots carries a 2-phase distributed winding. Each coil is short pitched by one slot. The winding factor is given by _____________

A

cot15°/3√2

B

cot15°/4

C

cot15°/2√2

D

cot15°/4

What is the spacing between the brushes for a wave winding when a machine is 6-pole DC armature with 16 slots having 2-coil sides per slot and single-turn coils.

A

4 segments

B

8 segments

C

16 segments

D

12 segments

A uniformly distributed winding on the stator has three full pitched coils, each coil having N turns and each turn carrying a current i. The MMF produced by the winding is?

A

sinusoidal in waveform with an amplitude 3Ni

B

sinusoidal in waveform with an amplitude 3Ni/2

C

trapezoidal in waveform with an amplitude of 3Ni

D

trapezoidal in waveform with an amplitude of 3Ni/2

For a wave winding when a machine is 6-pole DC armature with 16 slots having 2-coil sides per slot and single-turn coil, Yf value is ____

A

5

B

3

C

2

D

7

A series resonant band-pass filter consists of a 2 mH coil, a 0.005 µF capacitor and a 120 Ω resistor. The winding resistance of the coil is 12 Ω. The output voltage is taken off the resistor. Input voltage is 12 V_rms. What is the output voltage magnitude at the center frequency (f₀)?

A

10.9 V

B

1.09 V

C

1.1 V

D

12 V

What is the value of Yf for a lap winding with a 4-pole, 12-slot armature with two coil sides/slot? (Assume single-turns coils – progressive winding)

A

3

B

5

C

7

D

9

For a four pole, 16 slot armature with two coil-side/slot having wave connected progressive winding has single turn coils has simplex winding. The number of current paths is?

A

2

B

6

C

3

D

4

A large circular coil of N turns and radius R carries a time varying current $$I = {I_0}\sin \left( {\omega t} \right).$$ A small circular coil of n turns and radius r(r ≪ R) is placed at the centre of the large coil such that the coils are concentric and coplanar. The induced emf in the small coil

A

leads the current in the large coil by $$\frac{\pi }{2}$$

B

lags the current in the large coil by $$\pi $$

C

is in phase with the current in the large coil

D

lags the current in the large coil by $$\frac{\pi }{2}$$

A series resonant band-stop filter consists of a 68 Ω resistor, a 110 mH coil, and a 0.02 µF capacitor. The internal resistance, RW, of the coil is 4 Ω. Input voltage is 200 mV. Output voltage is taken across the coil and capacitor in series. What is the output voltage magnitude at f0?

A

1.1 mV

B

11.1 mV

C

111 mV

D

200 mV